Foldable high gain antenna system



Nov. 12, 1957 J. V. FISHER FOLDABLE HIGH GAIN ANTENNA SYSTEM 5Sheets-Sheet l Filed July 23' 1954 dans-PH u. -syse 4 7- rae/sys A N N ET N A N I A G VH .G I H E L B A D .L O F Nov. 12, 1957 m www W qw ,U1 wf Q5/W@ Eknlllll-IIIII.

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BY l Y .Nov. 12, 1957 .1.v. FISHER FOLDABLE HIGH GAIN ANTENNA SYSTEM 5Sheets-Sheet 3 Filed July 23, 1954 JNVENTOR.

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United States Patent `FoiooAnipn HIGH GAIN ANTENNA SYSTEM i Joseph V.Fisher, Pittsburgh, Pa. `Ammannati July z3, 1954, serial No. 445,260 7Claims. (Ci. 343-915) This invention relates to antennas, and moreparticularly to an improved wide band antenna suitable for reception oftelevision channels and for FM reception.

A main object of the invention is to provide a novel and improved wideband antenna for television and FM, said antenna being simple inconstruction, involving a minimum of electrical and mechanical parts,providing high gain, and being foldable to a relatively compact size fortransportation or storage.

A further object of the invention is to provide an improved multiple bayhigh gain wide band antenna of the type employing `a reflector screen,said antenna being inexpensive to fabricate, being rugged inconstruction, involving `substantially no corrosive joints, and which iseasily adjustable, particularly with reference to ultra high frequencychannels, so that a desired sharpness of the ultra high frequency fieldpattern may be obtained by adjusting the antenna. t

A still further object `of the invention is to provide an improvedmultiple bay high gain, wide band antenna array which employs areflector screen of the lattice type, the improved antenna array beingfoldable to a rela tively compact size` for transportation or storage,the improved antenna array involving relatively simple components, beingeasy to setup for use, and providing eiiicient reception of televisionand FM signals. i

A still further object of the invention is to provide an improved wideband, .high gain antenna of the type employing a reflector screen of thelattice type, said antenna being neat in appearance, being relativelylight in weight, and being arranged so that only one transmission lineis required over the entire spectrum received by the antenna.

, Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

Figure 1 is a perspective view of a two-bay antenna constructed inaccordance with the present invention, `shown set up for use.

Figure 2 is an enlarged cross sectional detail view taken on the line2-2 of Figure l.

Figure 3 is an enlarged cross sectional detail view taken on the line 33 of Figure 1.

' Figure 4 is a perspective view of a modified form of antennaconstructed in accordance with the present invention. i

Figure 5 is an enlarged fragmentary side elevational view of the antennashown in Figure 4.

Figure 6 is a rear elevational view of a further modified form ofantenna constructed in accordance with the present invention.

Figure 7 is a fragmentary rear elevational view of a still furthermodication of antenna according to the present invention.

Figure 8 is an enlarged cross sectional detail view taken on the line 83 of Figure 7.

Referring to the drawings, `and more particularly to ,Figures 1,12 and3, 1-1 designates one form of improved 2,813,268 Patented Nov. l2, 1957antenna according to the present invention. The antenna 11 is of themultiple bay typeand may comprise, for example, two bays stacked oneabove the other and supported on a vertical mast 12, the respective baysbeing designated at 13 and 14. The top bay 135 comprises a straightreiiector bar 17 of conductive material, for example, of aluminumtubing, and a pair of dipole elements designated at 18, 18, each dipoleelement comprising a conductive rod of aluminum or similar material,formed at an intermediate portion thereof with a U-shaped, relativelynarrow loop of substantial length, shown at 19. Respective insulators20, 20 rigidly connect the bight portions of the loops 19, 19 to thereiiector bar 17, the loops 19 being symmetrically located on oppositesides of the mid point of the reflector bar 17. The mid point of thereflector oar 17 is connected by a rigid bracket rod 21 to an insulator22, the inner ends of the respective dipole elements 1S, 18 beingsecured to the opposite ends of the insulator 22.

The outer portions of the respective dipole elements 1S, 1t; aresubsatntially V-shaped, as shown at 23, 23, facing away from thereflector bar 17. Respective rigid connecting rods 24, Z4 connect thereflector bar 17 to insulators 2S secured to the ends of the V-shapedportions 23 of the dipoles.

As is clearly shown in Figure 1, the inner portions 26 of the respectivedipoles are inclined inwardly toward reflector bars 17 and togetherdefine a V-shaped conguration similar to the configurations of therespective outer J -shaped dipole portions 23, 23.

All the elements thus far described, comprising `the reiiector bars 17,the dipoles 18, 1S, the respective loops 19, 19, and the bracketelements 24, 24 and 21 are in the same horizontal plane.

The reflector bars 17 may be of a length suitable for the televisionchannels to be received, for example, may be of a length substantiallyequal to one-half the wave length of the mid channel of thelower portionof the television spectrum, namely, the spectrum including channels 2 to6. The distance between the outer ends of the dipoles 18, 13 may besubstantially equal to the length of the reflector bar, namely, toone-half thewave length of the mid channel ofthe lower portion of thetelevision spectrum.

The lengths of the V-shaped portions 23, 23 and the V element defined bythe inner ends 26, 26 of the dipoles are substantially equalandcorrespond to onehalf of the Wave length of a particular frequency,for example, a frequency substantially in the middle of the upper V. H.F. television band, namely, the portion of the television spectrumincluding channels 7 to 13. Obviously, since the length of the V-shapedportions 23, 23 andthe V-shaped portion defined by the inner portions26, 26 of the dipoles are equal, each of the V-shaped elements thusdefined has a length approximately onethird that of the reflector bar 17The spacing of the main portions of 'the dipole elef ments 18, 13 fromthe reflector bar 17 is, of course, determined by the lengths of thebracketbars 24, 24, 21 and the 1oops 19, 1 9. In a typical embodiment ofthe invention, this length was approximately equal to a quarter wavelength of a middle channel in the upper portion of the V. H. F.television spectrum, namely, that portion of the television spectrumincluding the channels 7 to 13.

Obviously, a considerable range ofdimensions may be employed in choosingthe proper lengths of the reflector bar 17 and the dipole elements 18,18. For example, the retiector bar 17 may be of a length equal to thelength of one-half of the wave length for the lowest television channelof the spectrumto be covered and the lengths of the V-shaped portions23, 23, as well as the intermediate V-shaped portion defined by theinner end elements 25, 26 of the dipoles may be in accordance with thewave length of a particular channel in the upper portion of the V. H. F.television band, namely, in the band including channels 7 to 13, thespacing ofthe dipole elements 4from the reflector bar being similarlygoverned by the selected upper V. H. F. channel frequency and thespacing being one-quarter of the wave length of said selected frequency.

l The inner ends of the dipoles of the bays 13 and 14 are connected by apair of vertical harness conductors 27 and 28. A suitable insulator 31connects the intermediate portions of the harness conductors 27 and 28,suitable terminals 50 and j51 being provided at the intermediateportions of said harness conductors to which a transmission line may beconnected, or which may be employed for interconnecting the antenna bays13 and 14 with another pair of antenna bays to provide a four-bay array.

Designated at 38 and 40 are a pair of relatively small, ultra-highfrequency tuning loops which are adjustably mounted on the upperportions of the harness conductors 27 and 28 and which are provided withsuitable means 'for securing the loops in adjusted positions on saidharness conductor upper portions. A similar pair of relatively smalltuning loops 38 and 40 are adjustably mounted on the lower portions ofthe harness conductors 27 and 28 and are also provided with suitablemeans for securing said loops in adjusted positions on said lowerportions. The tuning loops 38, 40, 38 and 40 are angularly adjustablewith respect to the conductors 27 and 28 and are also adjustablevertically, whereby a desired tuning of the array to ultra highfrequency channels may be obtained. Since the bow loop elements 38, 40,38 and 40 are angularly adjustable as well as rotatable, they can be setat any desired angle so as to adjust the sharpness of the U. H. F. eldpattern of reception.

The bracket rods 21, extending perpendicularly from the mid point of therespective reflector rods 17 are electrically connected to saidreflector rods, forming a part thereof, and serve to keep out sidesignals, making the antenna array sharply directional. Similarly, therod elements 24, 24 are electrically connected to the reector bars 17,for the same purpose. An important feature of the construction of thereflector bays 13 and 14 is that the U-shaped elements 19 act lnot onlyas matching stubs but also take the place of the supporting rods andphasing harnesses employed in previously known antenna arrays.

The respective bays 13 and 14 may be separated by a desired Verticalspacing which is, of course, related to the signal wave lengths to bereceived. For example, the vertical spacing between the bays 13 and 14may be such that with respect to the lower portion of the V. H. F.television spectrum, the vertical spacing between the bays is equal toone-fifth of a wave length, for example, onefth of the mid Wave lengthin this portion of the band, or, alternatively, one-fifth of the lowestwave length in the band.

Designated respectively at 52 and 53 are respective rellector screensections of the lattice type which are hingedly connected respectivelyto the reflector bars 17 and 17 at 54 and 55. Each reilector screensection may comprise a pair of oppositely directed wires bent to formgenerally V-shaped elements 56, the wires being connected at theirmeeting bend portions 57, as by loop brackets 58 engaged around the bendportions 57, said loop brackets 58 being provided with overlappingapertured lug portions 59 which are connected by fastening bolts 60. Theclamping bolts 60 also serve to fasten the ends of respective supportingstraps 61 surrounding the associated reflector bar 17 or 17 to therebysecure the screen section to the reflector bar by means of theassociated bolt 60. A wing `nut 61 is provided'on the vend of the bolt,allowing the bolt .to be readily loosened when the assembly is to betaken apart or folded.

The bend portions of the lower wire of the upper section 52 and the bendportions of the upper wire ofthe lower screen section 53 are hingedlyconnected together at 65 in the manner shown in Figure 3. Thus, the bendportions of the lower wire of the upper screen section, designated at 66are received in looped straps 67, and the bend portions of the upperwire of the lower screen section, designated at 68 Aare received insimilar looped straps 69. The looped Straps 67 and 69 have apertured lugportions 70 and 71 which are overlapped and through which extend thefastening bolts 72 which are provided with' the wing nuts 73. Thus, thescreen may be at times folded on a horizontal axis located substantiallymidway between the reflector bars 17 and r17 to bring the reector barsand their associated pairs of dipole elements adjacent to each other(the harness conductors 27 and 28 being, of course, removed) whereby theantenna array may be collapsed to a relatively compact size fortransportation or storage. In installing the antenna, the reflectorAbars 17 and 17 are merely separated to their correct spacing, causingthe screen to be stretched to its proper, substantially coplanarcondition, whereupon the wing nuts 73 maybe tightened to lock the screenin `its coplanar condition. The harness conductors 27 and 28 may then beconnected to the antenna array in the manner shown in Figure 1, and thearray may then be fastened to the supporting mast 12, as by theconventional brackets and 80.

.In the modified form of the antenna shown in Figure 4, the screencomprises a pair of lattice sections and 91, each lattice sectioncomprising a plurality of spaced parallel conductive rods 92 which arerigidly connected to spaced vertical conductive rods 93, the rods 93 ofthe upper lattice section being connected at their lower ends r to thetop ends of the rods 93 of the lower lattice section as by bolts 94which are aligned on an axis substantially midway between the rellectorbars 17 and 17 and which serve as hinge connections for the latticesections when the bolts 94 are loosened. The bolts 94 are, of course,provided with wing .nuts 95 which may be tightened to lock the latticesections 90 and 91 in coplanar relationship, as shown in Figure 4. Theintermediate portions of the respective vertical bars 93 are secured tothe respective reflector bars 17 and 17' by fastening straps 96 whichare provided with apertured lugs 97 clamped to the bars 93 by fasteningbolts 98, as shown in Figure 5.

In the form of the invention shown in Figure 6, the upper and lowerreflector screen sections are designated respectively at 101 and 102 andare generally .similar in construction to the screen sections 52 and 53of Figure -1 except that the wires of the `screen sections .ane formedwith arcuately bowed bends 103 instead of having V- bends. The adjacentbends 103 are secured to the respective reflector bars 17 land 17' byfastening brackets 104, said brackets comprising straps which embracethe reflector bars 17 `and 17 and which are provided with suitable loopsin .which the arcuate wire bends are fastened.

The depending arcuate bends of the lower wire of the upper screen 101are connected to the upstanding arcuate bends of the upper wire of thelower screen section 102 by respective straps 67 and 69, and fasteningbolts 72 provided with wing nuts 73, as in Figures 1 and 3, defininghinge connections which are aligned along a line midway between thereector bars 17 and 17', allowing the reflector screen to be folded whenthe wing `nuts 73 are loosened. The connections 104 may be similar tothe corresponding connections employed at 54 and 55 in Figure 1, andillustrated in detail in Figure 2.

In the form of the invention shown in Figures 7 and 8, the rellectorscreen comprises an upper lattice section and-a lower lattice section111, .the upper lattice section being secured to the upper reflector bar17 and the ,lower `lattice .section being secured to the lower re- 75ector bar 17'. Each .lattice section comprises a pair of wires or rods112 and 113 bent to define successive alternating V elements, the Velements of the wires 12 and 13 being superimposed and being connectedb-y bolts or other suitable `fasteners at their intermediate portions,as shown at 114. As shown in Figure 8, the overlapping portions of thewires or rods 112 and 113 are flattened, as shown at 115 and 116, andoverlie the reflector rods 17 and 17', the fastening bolts 114 extendingthrough the reflector rods and through the flattened portions 115 and116 of the lattice rods, each bolt 114 being provided with a fasteningnut 118. The lowermost ends of the lattice rods of the upper reflectorscreen section 110 are connected to the uppermost bends of the latticerods of the lowermost screen section 111 by respective straps 67 and 69having overlapping apertured lug portions connected by fastening bolts72 provided with wing nuts 73, as illustrated in detail in Figure 3 andas employed in connection with the embodiment of the invention shown inFigure l. The connections of the upper lattice section 110 with thelower lattice section 111 are along a line spaced midway between thereflector bars 17 and 17', whereby the reflector screen may be folded toa collapsed position by loosening the wing nuts 73 as in the previouslydescribed forms of the invention.

`lt will be noted that each structural element of the array in each ofthe forms of the invention specifically described above has anelectrical function, and that a minimum amount of mechanical parts arethus required in order to complete the antenna assembly. This not onlyreduces the cost of the assembly but also considerably lightens itsweight, making it easier to erect the antenna andl rotate the same toobtain the desired orientation. The lightness of the antenna also makesit suitable for use with antenna rotating mechanisms of the conventionaltype.

While certain specific embodiments of an improved antenna has beendisclosed in the foregoing description, it will be understood thatvarious modifications within the spirit of the invention may occur tothose skilled in the art. Therefore, it is intended that no limitationsbe placed on the invention except as defined by the scope of theappended claims.

What is claimed is:

l. In an antenna of the character described, a pair of horizontalparallel reflector bars, respective pairs of dipole elements rigidlyconnected to and electrically associated with ysaid reflector bars inspaced substantially parallel relation thereto, each pair of dipoleelements being entirely in the same horizontal plane as one of saidreflector bars, respective lattice-like reflector screen sectionshingedly secured to the respective reflector bars, and means hingedlyconnecting said screen sections on a horizontal axis parallel to andlocated between said reflector bars, whereby the antenna may be at timesfolded to bring the reilector bars and their associated pairs of dipoleelements adjacent to and parallel to each other.

2. ln an antenna of the character described, a pair of horizontalparallel reflector bars, respective pairs of dipole elements rigidlyconnected to and electrically associated with said reflected bars inspaced substantially parallel relation thereto, each pair of dipoleelements being entirely in the same horizontal plane as one of saidreflector bars, respective lattice-like reflector screen sections hingedto the respective reflector bars, means hingedly connecting the bottomof the upper screen section to the top of the lower screen section on ahorizontal axis parallel to and located between said reflector bars,each dipole element comprising a conductor rod formed at an intermediateportion thereof with a matching stub comprising a U-shaped, relativelynarrow loop of substantial length, and respective insulators rigidlyconnecting the bight portions of said loops to the associated reilectorbars, said dipole elements being spaced symmetrically relative to themid points of their associated reflector bars.

i 3. In an antenna of the character described, a pair of horizontalparallel reflector bars, respective pairs of dipole elements rigidlyconnected to and electrically associated with said reflector bars inspaced. substantially parallel relation thereto, each pair of dipoleelements being entirely in the same horizontal plane as one of saidreflector bars, respective lattice-like reflector screen sections hingedto the respective reflector bars, means hingedly connecting the bottomof the upper screen section to the top of the lower screen `section on ahorizontal axis parallel to and located between said reflector bars,each dipole element comprising a conductor rod formed at an intermediateportion thereof with a matching stub comprising a U-shaped, relativelynarrow loop of substantial length, and respective insulators rigidlyconnecting the bight portions of said loops to the associated reflectorbar, said dipole elements being spaced symmetrically relative tothe midpoints of their associated reflector bars, the arm portion of eachdipole element located outwardly of its loop being substantiallyV-shaped and facing away from its associated reflector bar.

4, In an antenna of the character described, a pair of horizontalparallel reflector bars, respective pairs of dipole elements rigidlyconnected to and electrically associated with said reflector bars in`spaced substantially parallel relation thereto, each pair of dipoleelements being entirely in the same horizontal plane as one of saidrellector bars, respective lattice-like reilector screen Sections hingedto the respective reflector bars, means hingedly connecting the bottomof the upper screen section of the top of the lower screen section on ahorizontal axis parallel to and Vlocated between said reflector bars,each dipole element comprising a conductor rod formed at an intermediateportion thereof with a matching stub comprising a U-shaped, relativelynarrow loop of substantial length, respective insulators rigidlyconnecting the bight portions of said loops to the associated reilectorbar, said dipole elements being spaced symmetrically relative to the midpoints of their associated reflector bars, the arm portion of eachdipole element located outwardly of its loop being substantiallyV-shaped and facing away from its associated reflector bar, the armportion of each dipole element located inwardly of its loop beinginclined inwardly toward its associated reflector bar, and respectivevertical harness conductors connecting the ends of the inner armportions of the dipole elements.

5. In an antenna of the character described, a pair of horizontalparallel reflector bars, respective pairs of dipole elements rigidlyconnected to and electrically associated with said reflector bars inspaced substantially parallel relation thereto, each pair of dipoleelements being entirely in the same horizontal plane as one of saidreflector bars, respective lattice-like reflector screen sections hingedto the respective reflector bars, means hingedly connecting the bottomof the upper screen section to the top of the lower screen section on ahorizontal axis parallel to and located between said reflector bars,each dipole element comprising a conductor rod formed at an intermediateportion thereof with a matching stub comprising a U-shaped relativelynarrow loop of substantial length, respective insulators rigidlyconnecting the bight portions of said loops to the associated reflectorbar, said dipole elements being spaced symmetrically relative to the midpoints of their associated reflector bars, the arm portion of eachdipole element located outwardly of its loop being substantiallyV-shaped and facing away from its associated reflector bar, the anmportion of each dipole element located inwardlly of its loop beinginclined inwardly toward its associated reflector bar, respectivevertical harness conductors connecting the ends of the inner armportions of the dipole elements, and a relatively small, closedconductor loop element mounted on each harness conductor.

6. ln au antenna of the character described, a pair of horizontal,parallel reflector bars, respective pairs of dipole. elements rigidlyconnected to and electrically associlated with said reflector bars inspaced substantially parallel relation thereto, each pair of dipoleelements being entirely' in the same horizontal plane as one of saidreector bars, respective, lattice-like reector screen sections hingedtoA the respective reilector bars, means hingedly connecting the bottomof the upper screen section to theV top of the lower screen section on ahorizontal axis parallel to-` and, located midway between said reflectorbars, each dipole element comprising a conductor rod formed at anintermediate portion thereof with a matching stub comprising a U-shapedrelatively narrow loop .of substantial length, respective insulatorsrigidly connecting the bight portions of said loops to the associatedrelector bar said dipole elements being spaced symmetricallytrclative tothe mid points of their associated reector bars the arm portion of eachdipole element located outwardly of its loop being substantiallyV-shaped and facing away from its associated reector bar, the armportion of each dipole element located inwardly of its loop beinginclined inwardly toward -its associated reflector bar, respectiveinsulators rigidly connecting the ends of the inner arm portions of therespective pairs of dipole elements, and respective horizontaltransverse conductive support elements connecting said last-namedinsulators to the mid points of the respective reflector bars.

7. In an antenna of the character described, a pair of parallelreflector bars, respective pairs of dipole elements rigidly connected toand electrically associated with said reector bars in spacedvsubstantially parallel relation thereto, each pair of dipole elementsbeing entirely in the same horizontal plane as one of said reilectorbars, respective lattice-like reflector screen sections hinged to therespective reflector bars, means hingedly connecting the bottom of theupper screen section to the top of the lower screen, section on. ahorizontal axis parallel to and locatedy midway between said reectorbars, each dipole element comprisingl a` conductor rod formed at anintermedia-te portion thereof with armatching stub cornprising aU-shaped, relatively narrow loop of substantial length, respectiveinsulators rigidly connecting the bight portions of said loops to theassociated reflector bar, said dipolel elements being spacedsymmetrically relative to thernid points of their associated reectorbars, the `arm portion-.of each dipole element located outwardly of itsloop being'z substantially V-shaped and facing away from it-s associatedreflector bar, the arm portion of each dipole element located inwardlyof its loop being inclined inwardly towards its associated reflectorbar, respectivc vertical; harness conductors connecting, the ends of theinner anm portions of the dipole elements, respective insulators rigidlyconnecting the ends of the inner arm portions of the respective pairs ofdipole elements, respective horizontal transverse conductive supportelements connecting said last-named insulators to the mid points of therespective retlector bars and being electrically connected to saidreflector bars, respective additional insulators connected to the bendsof the V-shaped outer arm portions, and respective additional horizontaltransverse conductive support elements connecting said last-namedadditional insulators to the respective reector bars and beingelectrically connected to said reilcctor bars.

References Cited in the tile of this patent UNITED STATES. PATENTS2,270,314 Kraus Jan. 20, 1942 2,586,276 UmStead Feb. 19,l 1952 2,655,599Finncburgh m Oct. 13, 1953

